Universe

10 pages, 2562 KiB

Open AccessArticle

From Heavy-Ion Collisions to Compact Stars: Equation of State and Relevance of the System Size

by Sylvain Mogliacci, Isobel Kolbé and W. A. Horowitz

Universe 2018, 4(1), 14; https://doi.org/10.3390/universe4010014 - 23 Jan 2018

Cited by 3 | Viewed by 3025

In this article, we start by presenting state-of-the-art methods allowing us to compute moments related to the globally conserved baryon number, by means of first principle resummed perturbative frameworks. We focus on such quantities for they convey important properties of the finite temperature [...] Read more.

In this article, we start by presenting state-of-the-art methods allowing us to compute moments related to the globally conserved baryon number, by means of first principle resummed perturbative frameworks. We focus on such quantities for they convey important properties of the finite temperature and density equation of state, being particularly sensitive to changes in the degrees of freedom across the quark-hadron phase transition. We thus present various number susceptibilities along with the corresponding results as obtained by lattice quantum chromodynamics collaborations, and comment on their comparison. Next, omitting the importance of coupling corrections and considering a zero-density toy model for the sake of argument, we focus on corrections due to the small size of heavy-ion collision systems, by means of spatial compactifications. Briefly motivating the relevance of finite size effects in heavy-ion physics, in opposition to the compact star physics, we present a few preliminary thermodynamic results together with the speed of sound for certain finite size relativistic quantum systems at very high temperature. Full article

(This article belongs to the Special Issue Compact Stars in the QCD Phase Diagram)

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9 pages, 1022 KiB

Open AccessFeature PaperArticle

Scaling Properties of the Mean Multiplicity and Pseudorapidity Density in e⁻+e⁺, e^±+p, p( p ¯ )+p, p+A and A+A(B) Collisions

by Roy A. Lacey, Peifeng Liu, Niseem Magdy, Máté Csanád, Benjamin Schweid, Nuggehalli N. Ajitanand, John Alexander and Robert Pak

Universe 2018, 4(1), 22; https://doi.org/10.3390/universe4010022 - 22 Jan 2018

Cited by 17 | Viewed by 2632

Abstract

The charged-particle pseudorapidity density (

d N_{ch} / d η

) for p(

\bar{p}

)+p, p+A and A+A(B) collisions and the mean multiplicity

⟨ N_{ch} ⟩

for e

^{-}

+e

^{+}

,

e^{\pm} + p

, and p( [...] Read more.

The charged-particle pseudorapidity density (

d N_{ch} / d η

) for p(

\bar{p}

)+p, p+A and A+A(B) collisions and the mean multiplicity

〈 N_{ch} 〉

for e

^{-}

+e

^{+}

,

e^{\pm} + p

, and p(

\bar{p}

)+p collisions are studied for a wide range of beam energies (

\sqrt{s}

). Characteristic scaling patterns are observed for both

d N_{ch} / d η

and

〈 N_{ch} 〉

, consistent with a thermal particle production mechanism for the bulk of the soft particles created in all of these systems. The scaling patterns found also validate an essential role for quark participants in these collisions. The measured values for

d N_{ch} / d η

and

〈 N_{ch} 〉

are observed to factorize into contributions that depend on

log (\sqrt{s})

and the number of nucleon or quark participant pairs

N_{pp}

. The quantification of these contributions gives expressions that serve to systematize

d N_{ch} / d η

and

〈 N_{ch} 〉

measurements spanning nearly 4 orders of magnitude in

\sqrt{s}

and to predict their values as a function of

\sqrt{s}

and

N_{pp}

. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

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22 pages, 682 KiB

Open AccessArticle

Constraints on Dark Energy Models from Galaxy Clusters and Gravitational Lensing Data

by Alexander Bonilla and Jairo E. Castillo

Universe 2018, 4(1), 21; https://doi.org/10.3390/universe4010021 - 22 Jan 2018

Cited by 12 | Viewed by 4039

Abstract

The Sunyaev–Zel’dovich (SZ) effect is a global distortion of the Cosmic Microwave Background (CMB) spectrum as a result of its interaction with a hot electron plasma in the intracluster medium of large structures gravitationally viralized such as galaxy clusters (GC). Furthermore, this hot [...] Read more.

The Sunyaev–Zel’dovich (SZ) effect is a global distortion of the Cosmic Microwave Background (CMB) spectrum as a result of its interaction with a hot electron plasma in the intracluster medium of large structures gravitationally viralized such as galaxy clusters (GC). Furthermore, this hot gas of electrons emits X-rays due to its fall in the gravitational potential well of the GC. The analysis of SZ and X-ray data provides a method for calculating distances to GC at high redshifts. On the other hand, many galaxies and GC produce a Strong Gravitational Lens (SGL) effect, which has become a useful astrophysical tool for cosmology. We use these cosmological tests in addition to more traditional ones to constrain some alternative dark energy (DE) models, including the study of the history of cosmological expansion through the cosmographic parameters. Using Akaike and Bayesian Information Criterion, we find that the

w C D M

and

Λ C D M

models are the most favoured by the observational data. In addition, we found at low redshift a peculiar behavior of slowdown of the universe, which occurs in dynamical DE models when we use data from GC. Full article

(This article belongs to the Special Issue Progress in Cosmology in the Centenary of the 1917 Einstein Paper)

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33 pages, 421 KiB

Open AccessReview

Higher Spins without (Anti-)de Sitter

by Stefan Prohazka and Max Riegler

Universe 2018, 4(1), 20; https://doi.org/10.3390/universe4010020 - 19 Jan 2018

Cited by 11 | Viewed by 3121

Abstract

Can the holographic principle be extended beyond the well-known AdS/CFT correspondence? During the last couple of years, there has been a substantial amount of research trying to find answers for this question. In this work, we provide a review of recent developments of [...] Read more.

Can the holographic principle be extended beyond the well-known AdS/CFT correspondence? During the last couple of years, there has been a substantial amount of research trying to find answers for this question. In this work, we provide a review of recent developments of three-dimensional theories of gravity with higher spin symmetries. We focus in particular on a proposed holographic duality involving asymptotically flat spacetimes and higher spin extended

{bms}_{3}

symmetries. In addition, we also discuss developments concerning relativistic and nonrelativistic higher spin algebras. As a special case, Carroll gravity will be discussed in detail. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

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53 pages, 879 KiB

Open AccessEditor’s ChoiceArticle

The ABC of Higher-Spin AdS/CFT

by Simone Giombi, Igor R. Klebanov and Zhong Ming Tan

Universe 2018, 4(1), 18; https://doi.org/10.3390/universe4010018 - 19 Jan 2018

Cited by 31 | Viewed by 3844

Abstract

In recent literature, one-loop tests of the higher-spin AdS

_{d + 1}

/CFT

_{d}

correspondences were carried out. Here, we extend these results to a more general set of theories in

d > 2

. First, we consider the Type B higher spin [...] Read more.

In recent literature, one-loop tests of the higher-spin AdS

_{d + 1}

/CFT

_{d}

correspondences were carried out. Here, we extend these results to a more general set of theories in

d > 2

. First, we consider the Type B higher spin theories, which have been conjectured to be dual to CFTs consisting of the singlet sector of N free fermion fields. In addition to the case of N Dirac fermions, we carefully study the projections to Weyl, Majorana, symplectic and Majorana–Weyl fermions in the dimensions where they exist. Second, we explore theories involving elements of both Type A and Type B theories, which we call Type AB. Their spectrum includes fields of every half-integer spin, and they are expected to be related to the

U (N) / O (N)

singlet sector of the CFT of N free complex/real scalar and fermionic fields. Finally, we explore the Type C theories, which have been conjectured to be dual to the CFTs of p-form gauge fields, where

p = \frac{d}{2} - 1

. In most cases, we find that the free energies at

O (N^{0})

either vanish or give contributions proportional to the free-energy of a single free field in the conjectured dual CFT. Interpreting these non-vanishing values as shifts of the bulk coupling constant

G_{N} \sim 1 / (N - k)

, we find the values

k = - 1, - 1 / 2, 0, 1 / 2, 1, 2

. Exceptions to this rule are the Type B and AB theories in odd d; for them, we find a mismatch between the bulk and boundary free energies that has a simple structure, but does not follow from a simple shift of the bulk coupling constant. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

27 pages, 341 KiB

Open AccessArticle

Higher Spin Superfield Interactions with the Chiral Supermultiplet: Conserved Supercurrents and Cubic Vertices

by Ioseph L. Buchbinder, S. James Gates and Konstantinos Koutrolikos

Universe 2018, 4(1), 6; https://doi.org/10.3390/universe4010006 - 10 Jan 2018

Cited by 56 | Viewed by 2878

Abstract

We investigate cubic interactions between a chiral superfield and higher spin superfields corresponding to irreducible representations of the

4 D, N = 1

super-Poincaré algebra. We do this by demanding an invariance under the most general transformation, linear in the chiral superfield. [...] Read more.

We investigate cubic interactions between a chiral superfield and higher spin superfields corresponding to irreducible representations of the

4 D, N = 1

super-Poincaré algebra. We do this by demanding an invariance under the most general transformation, linear in the chiral superfield. Following Noether’s method we construct an infinite tower of higher spin supercurrent multiplets which are quadratic in the chiral superfield and include higher derivatives. The results are that a single, massless, chiral superfield can couple only to the half-integer spin supermultiplets

(s + 1, s + 1 / 2)

and for every value of spin there is an appropriate improvement term that reduces the supercurrent multiplet to a minimal multiplet which matches that of superconformal higher spins. On the other hand a single, massive, chiral superfield can couple only to higher spin supermultiplets of type

(2 l + 2, 2 l + 3 / 2)

(only odd values of s,

s = 2 l + 1

) and there is no minimal multiplet. Furthermore, for the massless case we discuss the component level higher spin currents and provide explicit expressions for the integer and half-integer spin conserved currents together with a R-symmetry current. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

3 pages, 185 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Universe in 2017

by Universe Editorial Office

Universe 2018, 4(1), 16; https://doi.org/10.3390/universe4010016 - 10 Jan 2018

Viewed by 2462

Abstract

Peer review is an essential part in the publication process, ensuring that Universe maintains high quality standards for its published papers.[...] Full article

28 pages, 1032 KiB

Open AccessArticle

Gravitational Waves, μ Term and Leptogenesis from B − L Higgs Inflation in Supergravity

by Constantinos Pallis

Universe 2018, 4(1), 13; https://doi.org/10.3390/universe4010013 - 9 Jan 2018

Cited by 16 | Viewed by 3294

Abstract

We consider a renormalizable extension of the minimal supersymmetric standard model endowed by an R and a gauged

B - L

symmetry. The model incorporates chaotic inflation driven by a quartic potential, associated with the Higgs field which leads to a spontaneous breaking [...] Read more.

We consider a renormalizable extension of the minimal supersymmetric standard model endowed by an R and a gauged

B - L

symmetry. The model incorporates chaotic inflation driven by a quartic potential, associated with the Higgs field which leads to a spontaneous breaking of U(1)

_{B - L}

, and yields possibly detectable gravitational waves. We employ quadratic Kähler potential with a prominent shift-symmetric part proportional to

c_{-}

and a tiny violation, proportional to

c_{+}

, included in a logarithm with prefactor

- N < 0

. An explanation of the

μ

term of the MSSM is also provided, consistently with the low energy phenomenology, under the condition that one related parameter in the superpotential is somewhat small. Baryogenesis occurs via non-thermal leptogenesis which is realized by the inflaton’s decay to the lightest or next-to-lightest right-handed neutrino with masses lower than

1.8 \times 10^{13}

GeV. Our scenario can be confronted with the current data on the inflationary observables, the baryon asymmetry of the universe, the gravitino limit on the reheating temperature and the data on the neutrino oscillation parameters, for 0.012 ≲

c_{+}

/

c_{-}

≲ 1/N and gravitino as light as 1 TeV. Full article

(This article belongs to the Special Issue Inflationary Universe Models: Predictions and Observations)

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11 pages, 321 KiB

Open AccessArticle

Pure-Connection Gravity and Anisotropic Singularities

by Kirill Krasnov and Yuri Shtanov

Universe 2018, 4(1), 12; https://doi.org/10.3390/universe4010012 - 4 Jan 2018

Cited by 2 | Viewed by 2589

Abstract

In four space-time dimensions, there exists a special infinite-parameter family of chiral modified gravity theories. They are most properly described by a connection field, with space-time metric being a secondary and derived concept. All these theories have the same number of degrees of [...] Read more.

In four space-time dimensions, there exists a special infinite-parameter family of chiral modified gravity theories. They are most properly described by a connection field, with space-time metric being a secondary and derived concept. All these theories have the same number of degrees of freedom as general relativity, which is the only parity-invariant member of this family. Modifications of general relativity can be arranged so as to become important in regions with large curvature. In this paper, we review how a certain simple modification of this sort can resolve the Schwarzschild black-hole and Kasner anisotropic singularities of general relativity. In the corresponding solutions, the fundamental connection field is regular in space-time. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

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6 pages, 1088 KiB

Open AccessArticle

Lévy Analysis of HBT Correlation Functions in s N N = 62 GeV and 39 GeV Au + Au Collisions at PHENIX

by Dániel Kincses

Universe 2018, 4(1), 11; https://doi.org/10.3390/universe4010011 - 4 Jan 2018

Cited by 10 | Viewed by 2773

Abstract

The phase diagram of strongly interacting matter can be explored by analyzing data of heavy-ion collisions at different center of mass collision energies. For investigating the space-time structure of the hadron emission source, Bose-Einstein or HBT correlation measurements are among the best tools. [...] Read more.

The phase diagram of strongly interacting matter can be explored by analyzing data of heavy-ion collisions at different center of mass collision energies. For investigating the space-time structure of the hadron emission source, Bose-Einstein or HBT correlation measurements are among the best tools. In this paper we present the latest results from the PHENIX experiment of the Relativistic Heavy Ion Collider (RHIC) on such measurements in

\sqrt{s_{N N}} =

39 GeV and 62 GeV Au + Au collisions. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

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8 pages, 254 KiB

Open AccessArticle

Entropic Distance for Nonlinear Master Equation

by Tamás Sándor Biró, András Telcs and Zoltán Néda

Universe 2018, 4(1), 10; https://doi.org/10.3390/universe4010010 - 4 Jan 2018

Cited by 4 | Viewed by 2668

Abstract

More and more works deal with statistical systems far from equilibrium, dominated by unidirectional stochastic processes, augmented by rare resets. We analyze the construction of the entropic distance measure appropriate for such dynamics. We demonstrate that a power-like nonlinearity in the state probability [...] Read more.

More and more works deal with statistical systems far from equilibrium, dominated by unidirectional stochastic processes, augmented by rare resets. We analyze the construction of the entropic distance measure appropriate for such dynamics. We demonstrate that a power-like nonlinearity in the state probability in the master equation naturally leads to the Tsallis (Havrda–Charvát, Aczél–Daróczy) q-entropy formula in the context of seeking for the maximal entropy state at stationarity. A few possible applications of a certain simple and linear master equation to phenomena studied in statistical physics are listed at the end. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

7 pages, 228 KiB

Open AccessArticle

Hamiltonian Dynamics of Doubly-Foliable Space-Times

by Cecília Gergely, Zoltán Keresztes and László Árpád Gergely

Universe 2018, 4(1), 9; https://doi.org/10.3390/universe4010009 - 3 Jan 2018

Cited by 1 | Viewed by 2649

Abstract

The 2 + 1 + 1 decomposition of space-time is useful in monitoring the temporal evolution of gravitational perturbations/waves in space-times with a spatial direction singled-out by symmetries. Such an approach based on a perpendicular double foliation has been employed in the framework [...] Read more.

The 2 + 1 + 1 decomposition of space-time is useful in monitoring the temporal evolution of gravitational perturbations/waves in space-times with a spatial direction singled-out by symmetries. Such an approach based on a perpendicular double foliation has been employed in the framework of dark matter and dark energy-motivated scalar-tensor gravitational theories for the discussion of the odd sector perturbations of spherically-symmetric gravity. For the even sector, however, the perpendicularity has to be suppressed in order to allow for suitable gauge freedom, recovering the 10th metric variable. The 2 + 1 + 1 decomposition of the Einstein–Hilbert action leads to the identification of the canonical pairs, the Hamiltonian and momentum constraints. Hamiltonian dynamics is then derived via Poisson brackets. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

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4 pages, 193 KiB

Open AccessArticle

Parallels of Belated Recognition: Bolyai János and Károlyházy Frigyes

by György Kádár

Universe 2018, 4(1), 8; https://doi.org/10.3390/universe4010008 - 3 Jan 2018

Viewed by 2858

Abstract

There was an obvious parallelism between the lives of the two Hungarian men of science: János Bolyai a genial geometer and Frigyes Károlyházy a missionary of education in the field of modern physics. Both of them selected and solved a complex problem that [...] Read more.

There was an obvious parallelism between the lives of the two Hungarian men of science: János Bolyai a genial geometer and Frigyes Károlyházy a missionary of education in the field of modern physics. Both of them selected and solved a complex problem that was too difficult for the majority of scientists of their times. Their work was criticized authoritatively by high rank scientists of their discipline, which led to their withdrawal from science. The belated recognition of the Non-Euclidean geometry and the gravity inspired quantum-mechanical state reduction put these excellent achievements to their deserved right place. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

45 pages, 442 KiB

Open AccessReview

Higher Spin Fields in Hyperspace. A Review

by Dmitri Sorokin and Mirian Tsulaia

Universe 2018, 4(1), 7; https://doi.org/10.3390/universe4010007 - 3 Jan 2018

Cited by 14 | Viewed by 2754

Abstract

We give an introduction to the so-called tensorial, matrix or hyperspace approach to the description of massless higher-spin fields. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

35 pages, 395 KiB

Open AccessReview

On Exact Solutions and Perturbative Schemes in Higher Spin Theory

by Carlo Iazeolla, Ergin Sezgin and Per Sundell

Universe 2018, 4(1), 5; https://doi.org/10.3390/universe4010005 - 1 Jan 2018

Cited by 20 | Viewed by 2926

Abstract

We review various methods for finding exact solutions of higher spin theory in four dimensions, and survey the known exact solutions of (non)minimal Vasiliev’s equations. These include instanton-like and black hole-like solutions in (A)dS and Kleinian spacetimes. A perturbative construction of solutions with [...] Read more.

We review various methods for finding exact solutions of higher spin theory in four dimensions, and survey the known exact solutions of (non)minimal Vasiliev’s equations. These include instanton-like and black hole-like solutions in (A)dS and Kleinian spacetimes. A perturbative construction of solutions with the symmetries of a domain wall is also described. Furthermore, we review two proposed perturbative schemes: one based on perturbative treatment of the twistor space field equations followed by inverting Fronsdal kinetic terms using standard Green’s functions; and an alternative scheme based on solving the twistor space field equations exactly followed by introducing the spacetime dependence using perturbatively defined gauge functions. Motivated by the need to provide a higher spin invariant characterization of the exact solutions, aspects of a proposal for a geometric description of Vasiliev’s equation involving an infinite dimensional generalization of anti de Sitter space are revisited and improved. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

36 pages, 545 KiB

Open AccessArticle

A Note on Rectangular Partially Massless Fields

by Thomas Basile

Universe 2018, 4(1), 4; https://doi.org/10.3390/universe4010004 - 1 Jan 2018

Cited by 8 | Viewed by 2900

Abstract

We study a class of non-unitary

so (2, d)

representations (for even values of d), describing mixed-symmetry partially massless fields which constitute natural candidates for defining higher-spin singletons of higher order. It is shown that this class of [...] Read more.

We study a class of non-unitary

so (2, d)

representations (for even values of d), describing mixed-symmetry partially massless fields which constitute natural candidates for defining higher-spin singletons of higher order. It is shown that this class of

so (2, d)

modules obeys of natural generalisation of a couple of defining properties of unitary higher-spin singletons. In particular, we find out that upon restriction to the subalgebra

so (2, d - 1)

, these representations branch onto a sum of modules describing partially massless fields of various depths. Finally, their tensor product is worked out in the particular case of

d = 4

, where the appearance of a variety of mixed-symmetry partially massless fields in this decomposition is observed. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

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10 pages, 326 KiB

Open AccessArticle

Universal Hyperbolic Geometry, Sydpoints and Finite Fields: A Projective and Algebraic Alternative

by Norman J. Wildberger

Universe 2018, 4(1), 3; https://doi.org/10.3390/universe4010003 - 1 Jan 2018

Cited by 2 | Viewed by 5045

Abstract

Universal hyperbolic geometry gives a purely algebraic approach to the subject that connects naturally with Einstein’s special theory of relativity. In this paper, we give an overview of some aspects of this theory relating to triangle geometry and in particular the remarkable new [...] Read more.

Universal hyperbolic geometry gives a purely algebraic approach to the subject that connects naturally with Einstein’s special theory of relativity. In this paper, we give an overview of some aspects of this theory relating to triangle geometry and in particular the remarkable new analogues of midpoints called sydpoints. We also discuss how the generality allows us to consider hyperbolic geometry over general fields, in particular over finite fields. Full article

(This article belongs to the Special Issue BGL2017: 10th Bolyai-Gauss-Lobachevsky Conference on Non-Euclidean Geometry and Its Applications)

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17 pages, 345 KiB

Open AccessFeature PaperArticle

A Note on (Non)-Locality in Holographic Higher Spin Theories

by Dmitry Ponomarev

Universe 2018, 4(1), 2; https://doi.org/10.3390/universe4010002 - 1 Jan 2018

Cited by 64 | Viewed by 3167

Abstract

It was argued recently that the holographic higher spin theory features non-local interactions. We further elaborate on these results using the Mellin representation. The main difficulty previously encountered in this method is that the Mellin amplitude for the free theory correlator is ill-defined. [...] Read more.

It was argued recently that the holographic higher spin theory features non-local interactions. We further elaborate on these results using the Mellin representation. The main difficulty previously encountered in this method is that the Mellin amplitude for the free theory correlator is ill-defined. To resolve this problem, instead of literally applying the standard definition, we propose to define this amplitude by linearity using decompositions, where each term has the associated Mellin amplitude well-defined. Up to a sign, the resulting amplitude is equal to the Mellin amplitude for the singular part of the quartic vertex in the bulk theory and, hence, can be used to analyze bulk locality. From this analysis we find that the scalar quartic self-interaction vertex in the holographic higher spin theory has a singularity of a special form, which can be distinguished from generic bulk exchanges. We briefly discuss the physical interpretation of such singularities and their relation to the Noether procedure. Full article

(This article belongs to the Special Issue Higher Spin Gauge Theories)

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405 KiB

Open AccessConference Report

Charged ρ Meson Condensate in Neutron Stars within RMF Models

by Konstantin A. Maslov, Evgeni E. Kolomeitsev and Dmitry N. Voskresensky

Universe 2018, 4(1), 1; https://doi.org/10.3390/universe4010001 - 26 Dec 2017

Viewed by 2785

Abstract

Knowledge of the equation of state (EoS) of cold and dense baryonic matter is essential for the description of properties of neutron stars (NSs). With an increase of the density, new baryon species can appear in NS matter, as well as various meson [...] Read more.

Knowledge of the equation of state (EoS) of cold and dense baryonic matter is essential for the description of properties of neutron stars (NSs). With an increase of the density, new baryon species can appear in NS matter, as well as various meson condensates. In previous works, we developed relativistic mean-field (RMF) models with hyperons and

Δ

-isobars, which passed the majority of known experimental constraints, including the existence of a

2 M_{⊙}

neutron star. In this contribution, we present results of the inclusion of

ρ^{-}

-meson condensation into these models. We have shown that, in one class of the models (so-called KVOR-based models, in which the additional stiffening procedure is introduced in the isoscalar sector), the condensation gives only a small contribution to the EoS. In another class of the models (MKVOR-based models with additional stiffening in isovector sector), the condensation can lead to a first-order phase transition and a substantial decrease of the NS mass. Nevertheless, in all resulting models, the condensation does not spoil the description of the experimental constraints. Full article

(This article belongs to the Special Issue Compact Stars in the QCD Phase Diagram)

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